'\" et
.TH net_if.h "0P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\"
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.\"
.SH NAME
net/if.h
\(em sockets local interfaces
.SH SYNOPSIS
.LP
.nf
#include <net/if.h>
.fi
.SH DESCRIPTION
The
.IR <net/if.h> 
header shall define the
.BR if_nameindex
structure, which shall include at least the following members:
.sp
.RS 4
.nf

unsigned  if_index  \fRNumeric index of the interface.\fR
char     *if_name   \fRNull-terminated name of the interface.\fR
.fi
.P
.RE
.P
The
.IR <net/if.h> 
header shall define the following symbolic constant for the length of
a buffer containing an interface name (including the terminating NULL
character):
.IP IF_NAMESIZE 12
Interface name length.
.P
The following shall be declared as functions and may also be defined as
macros. Function prototypes shall be provided.
.sp
.RS 4
.nf

void                  if_freenameindex(struct if_nameindex *);
char                 *if_indextoname(unsigned, char *);
struct if_nameindex  *if_nameindex(void);
unsigned              if_nametoindex(const char *);
.fi
.P
.RE
.LP
.IR "The following sections are informative."
.SH "APPLICATION USAGE"
None.
.SH "RATIONALE"
None.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
The System Interfaces volume of POSIX.1\(hy2017,
.IR "\fIif_freenameindex\fR\^(\|)",
.IR "\fIif_indextoname\fR\^(\|)",
.IR "\fIif_nameindex\fR\^(\|)",
.IR "\fIif_nametoindex\fR\^(\|)"
.\"
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
.PP
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
